Automotive Air Conditioning Information Forum

Hi all,


Thanks for having me aboard. I appreciate anyone's help trying to figure this one out.

Vehicle in question is a 2013 GMC Sierra Denali with just single zone AC. It cycles on for about 5 seconds then shuts off for a minute or more. Can't seem to pinpoint the problem.

I've evacuated, pulled vacuum for 30 mins, let it sit for 30 mins to confirm vacuum didnt bleed off, recharged with 25oz of R134. The compressor didnt want to turn on when adding the R134A so I manually bridged the A/C relay to force it to drink it. While I had it bridged the A/C was nice and cold.

Same issue as before I did the recharge. The A/C cycles on for about 5 seconds then shuts off for a minute. So on and so forth. never gets to a point where it actually puts out any cold air.

Bad pressure switch? Bad air temp switch?

Maybe check for any diagnostic codes stored in the ecm.

Thanks for the input. I thought about that too. No luck with any stored codes.

That's all I got. Same problem in my older car.